"The fourth-quarter operating income was up more than expected," said R.J. Hottovy, an equity analyst at Morningstar. "This supports the bull case that Amazon can monetize its growth over the longer term."

Amazon shares climbed 6.8 percent to $278 in after-hours trading following its results.

The company said fourth-quarter revenue jumped 22 percent to $21.27 billion as it grabbed a big share of online spending during the crucial holiday period.